The present invention relates generally to hospital beds and, more particularly, to a hospital bed having a force or weight sensor.
It is known for beds to have scales which automatically provide a patient's weight to a caregiver. Various types of such scales are known. See, for example, U.S. Pat. Nos. 6,208,250; 5,859,390; 5,173,977; 4,961,470; 4,281,730; 4,953,244; 4,793,428; 5,269,388; and 5,279,010 all of which are incorporated by reference herein. These scales allow caregivers to weigh patients without having them leave the bed. Some beds have built in weigh frames with load cells located beneath the weigh frames.
Many hospital beds permit articulation of their patient support decks for relative positioning or elevation of the head, legs, and feet of a patient to suit various therapeutic needs. Moreover, many hospital beds permit adjustment of their patient support decks from a normal horizontal position to an angled head down or head up position—so called “Trendelenburg” and “reverse Trendelenburg” positions, respectively. Some force sensors, such as load cells of a bed scale, are mounted to a movable frame of a bed instead of a stationary base frame. In such embodiments, when the movable frame is aligned at an angle, the measured weight of the patient is inaccurate because the direction of the weight force is not perpendicular to load cells of the weigh system.
An illustrative embodiment of the present invention provides a system which determines an angle of alignment of the movable frame in at least one direction and corrects the force measured by the force sensor to generate a corrected weight. Therefore, the system provides an accurate weight reading even when the movable frame of the bed is aligned at a non-horizontal angle.
Hospital beds with pressurized air mattresses are also common. Optimizing mattress pressures helps patients feel more comfortable. Additionally, providing optimum mattress pressures reduces interface pressure against the patient and therefore reduces the likelihood of bed sores and other problems associated with being bed ridden for long periods of time. A patient's size and weight are common factors for determining an optimum mattress pressure. Accordingly, some hospital beds have controllers programmed with several weight ranges and respective mattress pressures. In these systems, a caregiver manually inputs the patient's weight or presses a button corresponding to a weight range, and the controller then maintains predetermined pressures in the air mattress based on the weight setting. However, such beds require the caregiver to know the patient's weight and manually input the weight.
A further illustrative embodiment of the present invention provides a control system which automatically adjusts pressure in an inflatable portion of a patient support based on a patient's weight detected by a force sensor or other scale apparatus.
According to another illustrative embodiment of the present invention, an apparatus for supporting a patient is provided. The patient has a mass accelerated by gravity to produce a weight force having a vertical direction. The weight force is conceivable as a sum of component forces including a first force vector having a first magnitude, and a second force vector having a second magnitude. The first force vector has a first direction aligned at angle relative to the direction of the weight force, and the second force vector has a second direction perpendicular to the first direction. The apparatus includes a supply configured to receive a control signal and supply a compressible medium in response to the control signal, and a patient support including an inflatable portion coupled to the supply to receive the compressible medium therefrom. The inflatable portion is configured to be pressurized by the compressible medium. The apparatus further includes a pressure sensor coupled to the inflatable portion of the patient support to be exposed to the pressure therein, the pressure sensor being configured to generate a pressure signal in response to the pressure. A force sensor is positioned to detect the first magnitude of the first force vector, the force sensor being configured to generate a force signal in response to the first magnitude. A controller is coupled to the pressure sensor to receive the pressure signal therefrom and is coupled to the force sensor to receive the force signal therefrom. The controller is configured to generate the control signal in response to the pressure signal and the force signal.
According to a further illustrative embodiment of the present invention, a method for supporting a patient on a patient support is provided. The method comprises pressurizing at least a portion of the patient support with a compressible medium in response to a control signal, generating a pressure signal in response to a pressure of the compressible medium within the patient support, measuring a weight of the patient on the patient support, and generating the control signal in response to the pressure signal and the measured patient weight.
According to another illustrative embodiment of the present invention, an apparatus for supporting a patient is provided. The apparatus comprises a base, a frame, a patient support coupled to the frame, and a lift mechanism coupled to the base and the frame. The lift mechanism is configured to selectably elevate a first end of the patient support relative to a second end of the patient support. A force sensor is coupled to the patient support and is configured to generate a force signal in response to a detected force. The apparatus further comprises an angle sensor coupled to one of the frame and the patient support, the angle sensor being configured to generate an angle signal in response to an angle of the force sensor. A controller is coupled to the angle sensor to receive the angle signal therefrom and is coupled to the force sensor to receive the force signal therefrom. The controller is configured to generate a weight signal in response to the angle signal and the force signal. An output device is coupled to the controller to receive the weight signal therefrom and is configured to indicate a weight of the patient based on the weight signal.
According to another illustrative embodiment of the present invention, a method for supporting a patient on a patient support is provided. The patient support includes a first end and a second end. The patient has a mass accelerated by gravity to produce a weight force having a vertical direction. The weight force is conceivable as a sum of component vector forces including a first force vector and a second force vector. The first force vector has a first magnitude directed in a first direction at an angle relative to the direction of the weight force. The second force vector has a second magnitude directed in a second direction perpendicular to the first direction. The method comprises the steps of supporting the patient on the patient support, selectably elevating the first end of the patient support relative to the second end of the patient support, measuring an angle of the patient support, generating a weight signal in response to the angle of the first force vector and the first magnitude, and providing an indication of the weight signal.
According to another illustrative embodiment of the present invention, a method of supporting a patient on a patient support having at least one fluid-filled zone is provided. The method comprises the steps of detecting an actual pressure within the fluid-filled zone, measuring a weight of the patient on the patient support, and comparing the actual pressure within the fluid-filled zone to an optimum pressure of the fluid-filled zone based upon the measured patient weight. The method further comprises the step of adjusting the pressure within the fluid-filled zone, if necessary, based on the patient weight.
According to another illustrative embodiment of the present invention, a method of determining a weight of a patient located on a movable patient support is provided. The method comprising the steps of providing a scale to determine a weight value of the patient, determining an angle of the patient support, and adjusting the weight value detected by the scale based on the angle of the patient support.
A further illustrative embodiment of the present invention provides a method for determining and setting pressures for cushions or sections of a patient support. The method comprises the steps of measuring force exerted upon a seat section of the patient support and measuring an angle that a head section of the patient support assumes relative to horizontal. The method further comprises the steps of calculating the weight of a patient from the seat force measurement and the head section angle measurement. The method also comprises the steps of determining baseline pressure values of the sections based upon the calculated weight of the patient, and setting pressures in the sections to the determined baseline pressure values.
A further illustrative embodiment of the present invention provides a method of determining and setting pressures for cushions or sections of a patient support. The method comprises the steps of measuring force exerted upon a seat section of the patient support and measuring the angle that a head section of the patient support assumes relative to horizontal. The method further comprises the steps of comparing the force measurement and angle measurement to a set of predetermined values in a comparison table and determining the weight of a patient therefrom. The method also comprises the steps of determining baseline pressure values of the sections based upon the determined weight of the patient, and setting baseline pressures in the sections to the determined baseline pressure values.
Another illustrative embodiment of the present invention provides a patient support comprising a frame, and a deck supported by the frame having head, seat, and foot sections configured to articulate relative to each other. An inflatable mattress is supported by the deck and includes head, seat, and foot sections positioned above the head, seat, and foot sections of the deck. The patient support further comprises a force sensor configured to sense the force applied to the seat section of the mattress and an angle sensor configured to sense the angle of the head section of the deck relative to horizontal. The patient support also comprises a controller configured to receive input from the force sensor and the angle sensor and to determine the weight of a patient upon the patient support, the controller being further configured to determine baseline pressures for the sections of the mattress.
A further illustrative embodiment of the present invention provides a method of controlling a patient support having at least one fluid-filled zone. The method comprises the steps of detecting an actual pressure within the fluid-filled zone, providing a first force sensor configured to measure force applied to the patient support, and determining a first measured weight of a patient supported on the patient support from the first force sensor. The method further comprises the step of setting a baseline pressure within the fluid-filled zone based upon the first measured weight. The method also comprises the steps of providing a second force sensor configured to measure force applied to the patient support, determining a second measured weight of the patient from the second force sensor, and comparing the first measured weight to the second measured weight. The method further comprises the step of providing a diagnostic output if a differential between the first measured weight and the second measured weight exceeds a predetermined value.
Another illustrative embodiment of the present invention provides a patient support comprising a frame, a deck supported by the frame, and a first force sensor operably coupled to the deck and configured to provide a first force output indicative of force applied to the deck. A mattress is supported by the deck and includes a fluid-filled seat section. A second force sensor is operably coupled to the seat section of the mattress and is configured to provide a second force output indicative of force applied to the seat section. A controller is configured to receive the first force output and the second force output, the controller including a processor configured to determine a first measured weight of the patient in response to the first force output and to determine a second measured weight of the patient in response to the second force output. The processor is further configured to provide a diagnostic output if a differential between the first measured weight and the second measured weight exceeds a predetermined value.
In a further illustrative embodiment, a patient support comprises at least one deck section and at least one fluid receiving cushion coupled to the at least one deck section. A weight sensor is configured to detect the weight of a patient supported by the at least one fluid receiving cushion. An angle sensor is configured to determine an angle of the at least one deck section. A controller is configured to receive input from the weight sensor and the angle sensor and to set an inflation pressure for the at least one fluid receiving cushion.
Additional features of the invention will become apparent to those skilled in the art upon consideration of the following detailed description of illustrated embodiments exemplifying the best mode of carrying out the invention as presently perceived.